SmartWater based synergistic technologies for enhanced oil recovery

Abstract

Enhanced oil recovery (EOR) technologies based on chemicals and solvents require significant volume of source injection materials, and have limited applicability in difficult environments and harsh reservoir conditions. Synergizing injection water compositions in terms of salinity and ionic content (SmartWater) with existing recovery methods can become a game changer to overcome these limitations.The main objective is to explore the synergistic effects of SmartWater as a potential optimization avenue for achieving more efficient and economic EOR applications. To achieve this objective, a range of multiscale experimental data from macro- to core-scale were analyzed to demonstrate and quantify the benefits of water chemistry synergies with different recovery methods. The multiscale experimental data analyzed comprised of polymer rheology, contact angles, core floods, foam stability and rheology, besides evaluating the zeta potential results obtained from surface complexation modeling (SCM).The dilute concentrations of polymer ranging from 250 to 500 ppm in SmartWater increased the injection water viscosities by 2 to 4 times to provide better mobility control for light oil recovery. The tailored water chemistry reduced the polymer consumption requirements by one-third (from 3000 ppm to 2000 ppm) and increased the oil recovery by 5–7% in polymer flooding processes used for viscous oil recovery. Synergizing water chemistry with surfactant-polymer flooding resulted in an incremental oil recovery of about 4% besides lowering the surfactant and polymer concentrations by 50% (from 2000 ppm to 1000 ppm). SmartWater has also been found to synergistically combine with carbonated waterflooding to increase the CO2 dissolved volumes by 25–30% for effectively lowering the pH and develop favorable wettability alterations towards water-wet conditions. The tailored water chemistry increased the foam stabilities by resulting in 2–3 times higher foam half-lifes in addition to raising the foam apparent viscosities by 1.5 times. SmartWater foams also increased the pressure drops in porous media by 50% to confirm higher foam apparent viscosities and more resistance to gas flow.The benefits of different SmartWater based synergistic EOR technologies demonstrated in this study can be significant. They can deliver higher oil recoveries in addition to lowering the volume requirements of different EOR agents such as chemicals and gas. These findings will have a practical impact to result in more practical, efficient and economical EOR projects in the field.